Hi mother in law,
Sorry to hear about the problems concerning exdil.
Interesting that she didn't contact us. Does she know we can shoot her down in flames? Should we send a gentle but firm text saying if she had questions about the arrangements please contact us?
Has dil ever talked about her concerns or anger over situations in the past with you? Or is this just a pattern with her in which she vents her frustrations to someone who is not involved? This is a common tactic that is all too familiar to me. My uBPDmom would also do the same thing. When she was angry with my oldest sister, she would call me to tell me. I learned to set boundaries around this issue by telling her to call my sister directly and to not involve me. This took many "training" sessions as my uBPDmom did not want to honor my boundary. It finally did happen, though. I would suggest that your son set the boundary with exdil and this would remove him from the triangle. I don't know that texting her would give you the result you are looking for. It might only result in more anger towards you and could possibly lead to changes in your contact with gd. Just my thoughts on the situation.
There are some great articles on this site concerning communicating and setting boundaries with a BPD. You can find the links here:
https://bpdfamily.com/message_board/index.php?topic=69272.0 and
https://bpdfamily.com/content/values-and-boundaries.
Hope this helps.
Wishing you all the best!